Regulating means for mixed-pressure turbines



Feb. 6, 1923.

W. E. VER PLANCK. REGULATING MEANS FOR MIXED PRESSURE TURBINES.

FILED JULY 25.1921- I rw enter" I-Iis Attorneg.

Patented Feb. 6, 1323.

LM MW WILLIAM EVERETT VER PLANCK,

OF SCHENECTAJDY, NEW YORK, ASSIGNOR, TO

GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

REG'E 'ILA'J.IIING MEANS FOR MIXED-PRESSURE TURBINES.

Application filed July 25,

To all whom it may concern:

Be it known that I, WILLIAM VER PLANoK, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Regulating Means for Mixed-Pressure Tur bines, of which the following is a specification.

The present invention relates to elastic fluid turbines wherein whenever the turbine is operating with the usual supply of high pressure elastic fluid it utilizes also low pressure elastic fluid from any available sources of supply;

The object of my invention is to provide an improved structure and arrangement in a regulating arrangement of this character and for aconsiderat-ion of what I believe to be novel and my invention attention is directed to the accompanying description and the claims appended thereto.

In the drawing, the figure is adiagrammatic view of a. regulating arrangement embodying my invention.

Referring to the, drawing, 5 indicates an elastic fluid turbine having an admission conduit. 6 through which high pressure elastic fluid is admitted and an admission conduit 7 through which low pressure elastic fluid is admitted. Only the high pressure end of the turbine is shown'but it will be understood that it is a turbine of any suitable type and that it is provided with the usual exhaust opening at its low pressure end which may be connected to a condenser. The turbine shaft is indicated at 8.

'In conduit 6 is a control valve 9. a known type of balanced valve being indicated in the present instance. The stem 10 of valve 9 is connected to the piston of a servo-motor 11.. the cylinder of the motor being indicated at 12. In cylinder 12 is a spring 13 which acts on the piston in a direction to close valve 9. Admission of actuating fluid to cylinder 12 is controlled by a pilot valve 14: which moves ina pilot valve casing 15 and controls the connection between a port 16 which communicates with cylinder 12 and admission and discharge ports 17 and. 18 respectively. The pilot valve may be connected to,an v suitable type of governor for regulating the opening of valve 9 in accordance with the load on the turbine. In the present instance. the stem of the pilot EVERETT 1921. Serial No. 487,235.

valve is shown connected to a speed governor 19 through the intermediary of a governor lever 20. The illustration is diagrammatic only. It will be understood that the governor is arranged to be driven from turbine shaft 8 and that in actual practice the connections between the governor and pilot valve may include a usual follow up arrangement to prevent overtravel. The operation of a regulating valve by a governor arrangement as shown is well understood and needs no description, it being understood that when the pilot valve moves upward to admit operating fluid to cylinder 12,

' valve 9 will be opened against the action of spring 13," and that when the pilot valve moves downward to permit the escape of actuating fluid from cylinder 12, spring 13 will move valve 9 toward closed position.

In conduit 7 is a valve 21 having a stem 22 connected to a piston 23 which moves in a cylinder 24. In cylinder 24 is a spring 2:") which acts on piston 23 in a direction to move valve 21 toward closed position. In other words. valve 21 is biased to closed position by spring 25.

It is desirable that valve 21 be open whenever fluid pressure is admitted to cylinder 12 to open valve 9 and the pressure of the supply of low pressure elastic fluid is above a predetermined value, i. e., the pressure in conduit 7 in advance of valve 21 as regards the flow of elastic fluid. The arrangement is preferably such that valve 21 will open under lower pressure than valve 9 so that the turbine may run at light load on auxiliary elastic fluid only. On the other hand, it is desirable that valve 21 be closed in case the fluid pressure in cylinder 12 decreases below a predetermined value or the pressure of the low pressure elastic fluid falls below the predetermined value. To this end. 1 connect cylinder 12 to cylinder 24 by a conduit 26 having two parallel branches 2? and 28. In branch 27 is a valve 29 hav ng a stem 30 connected at its outer end to a diaphragm 31 contained in a casing 32. A spring 33 bears on the upper side of diaphragm 31 and serves to bias valve 29 to closed position. Casing. 32 below diaphragm 31 is connected to conduit 7 by a pipe 34. The pressure of the low pressure" elastic fluid in conduit 7 thus acts on diaphragm 31 in a direction to open valve 29 against the action of spring 33. In branch catch 41 which engages a lug '42 on arm 40.

Catch 41 is held in engagement with lug 42 by a rod 43,- the lower end of which rests on and is supported on a trip finger 44 pivoted at 45 on a casing 46. One end of the trip finger 44'terminates adjacent the head of a plunger 47 carried by shaft 8. Plunger 47 forms an emergency governor of known type, it being held against radial movement by a spring 48. In case of excess speed, the plunger is thrown radially outward by centrifugal force against the action of spring 48 to engage trip finger 44, and knock it from under rod 43. In casing 46 is a spring 49 which engages a collar 50 on rod 43 and acts in a direction to force rod 43 downward and move catch 41 from engagement with lug 42 whereupon weight 39 will open valve 38.

When the turbine is in operation, valve 9 will be held open to the required extent by valve 29 against the action of spring 33 thereby connecting cylinder 24 to cylinder 12 so that the fluid pressure acting to hold valve 9 open will act to open valve 21 and hold it open. -Should the fluid pressure in cylinder 12 berelieved to permit of the closing of valve 9, then valve 21 will be closed also by spring 25. It will thus be seen that valve 21 is opened only in case fluid pressure is available in cylinder 12 for opening valve 9 and that whenever this fluid pressure is released, valve 21 closes. The strength of spring 25 is preferably such that valve 21 will open with a pressure in conduit 26 slightly less than that required to start valve 9 to open. y this arrangement the turbine may be operated on low pressure elastic fluid alone at light loads On the other hand, even though valve 9 is open, valve 21 will not be opened unless the pressure in conduit 7 is above a predetermined value so valve 29 is open.

If when valves 9 and 21 are both open the pressure in conduit 7 falls below that required, valve 29 will close whereupon the fluid pressure on piston 23 will be dissipated by leakage through leak opening 36 and valve 21 closed. Upon the pressure being reestablished in conduit .7, valve 29 will be again opened thereby admitting pressure to cylinder 24 to again open valve 21. Branch pipe 28 forms a by pass around valve 29 and permits the fluid pressure under piston 23 to escape very quickly whenever the pressure in cylinder 12 is relieved, check valve 35 permitting flowaway from cylinder 24 but preventing flow through branch 28 toward cylinder 24.

The pressure in cylinder 12 may be relieved due to the shutting down of the turbine for example, or the tripping of the emergency mechanism shown. In the latter instance, in case of excess speed emergency governor 47 is thrown out by centrifugal force striking the end of trip linger 44 and knocking it from under rod 43. Spring 49 then forces rod 43 downward moving catch 41 from engagement with lug 42 and permitting weight 39 to open valve 38. The pressure in pipe 26 is thus quickly relieved through branch pipe 37 whereupon valves 9 and 21 will quickly close. 'The closing of valves 9 and 21 in case of excess speed maybe in addition to that of the usual emergency shut off valve generally provided as is well understood. The resetting of the emergency mechanism is. accomplished by raising weight 39 to close valve 38 and bring lug 42 into position to be engaged by latch 41 and then raising rod 43 to engage latch 41 with lug 42 and permit trip finger 44 to drop under rod 43.

In accordance with the provisions of the patent statutes, I have described the'principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

\Vhat I claim as new and desire to secure by Letters Patent of the United States, is:

1.'The combination with a prime mover having a conduit for the admission of high pressure elastic fluid. a conduit for the admission of low pressure elastic fluid, ahigh pressure valve in the first named conduit, and a low pressure valve in the second named conduit, of a fluid actuated motor for opening the high pressure valve, afluid actuated abutment for opening the low pressure valve, a pipe connecting the fluid actuated motor to the abutment. a valve in said pipe. and means controlled by the pressure in the low pressure conduit for regulating the opening of the last named valve.

2. The combination with a prime mover having a conduit for the admission of high pressure elastic fluid, a conduit for the admission of low pressure elastic fluid, a high pressure valve in the first named conduit, and a low pressure valve in the second named conduit, of a fluid actuated motor for opening the high pressure valve, a fluid actuated abutment for opening the low pres sure valve, a pipe connecting the fluid actuated motor to the abutment, a valve in said pipe, means controlled by the pressure in the lOW pressure conduit for regulating the opening of the last named valve, a by pass around the lastnamed valve, and a check valve in said by-pass which opens toward the fluid actuated motor.

' 3. The combination with a prime mover having a Conduit for the admission of high pressure elastic fluid, a conduit for the admission of low pressure elastic fluid, a high pressure valve in the first named conduit, and a low ressure valve in the second named conduit, ot a fluid actuated motor for opening the high pressure valve, a fluid actuated abutment for openin the low pressure valve, a' pipe connecting t e fluid actuated motor to the abutment, a valve in said pipe, means controlled by the pressure in the low pressure conduit for regulating the opening of the last named valve, and means controlled by the speed of the prime mover for relieving the pressure in said pipe.

4. The combination with a prime mover having a conduit for the admission of high pressure elastic fluid, a conduit for the ad mission of low pressure elastic: fluid, a high pressure valve in the first named conduit, and a low pressure valve in the second named conduit, of'a fluid actuated motor for opening the high pressure valve, a fluid actuated abutment for opening thelow. pressure valve,-a pipe connecting the fluid actuated motor to the abutment, a. valve in said pipe, means controlled by the pressure in the low pressure conduit for regulating the opening of the last named valve, a by pass around the last named valve, a check valve therein, a branch conduit connected to said pipe, a normally closed valve therein, and means operated in case of excess speed of the prime mover for effecting the opening of such valve.

5. The combination With a prime mover, of a conduit for the admission of high pressure elastic fluid, a conduit for the admission of low pressure elastic fluid, a. high pressure valve in the first named conduit, a low pressure valve in the second named conduit, means biasing said valves to closed positions, fluid-actuated abutments for opening said valves against the biasing means, a pipe connecting said abutments, means for regulating the admission of actuating fluid to the abutment connected to the high pressure valve, a valve in said pipe, and means controlled by the pressure of the low pressure elastic fluid for regulating the last named valve.

6. The combination with a prime mover, of a conduit for the admission of high pressure elastic fluid, a conduit for the admission of low pressure elastic fluid, a high pressure valve in the first named conduit, a low pressurevalve in the second named conduit, means biasin said valves to closed positions, fluid-actuate abutments for opening said valves against the biasing means, a pipe connecting said abutments, means for regulating the/admission of actuating fluid to the abutment connected to the high pressure valve, a valve in said pipe, means controlled by the pressure of the low pressure elastic fluid for regulating the last named valve, a by pass around said last named valve, and a check valve therein which opens toward the abutment connected to the high pressure valve.

In witness. whereof, I have hereunto set my hand this 22nd day of July, 1921.

I WlLLlAM EVERETT VIER NANCE. 

